Adhesive fastener elements are employed for a variety of purposes, such as in automotive technology, flooring technology and clothing of all kinds, and for special applications in mechanical engineering. Adhesive fastener elements provide reliable detachable connections and fastening elements in these fields. When such adhesive fastener elements are used for aircraft or motor vehicle passenger seats, they serve the purpose of fastening seat covers to foamed parts. Some adhesive fastener elements are foamed into the foam upholstery material during production of the respective seat, while the adhesive fastener element with the corresponding interlocking elements is fastened to the cover upholstery material, in particular is sewn on. When producing the foam body element, the adhesive fastener elements are introduced into seating pipes of a foam injection mold. By introduction of foam material into the free cross sections of the foam injection mold, preferably one of PU foam, the adhesive fastener elements are fastened on the foam body elements in the foam injection process. The pipes employed normally project above the other walls of the foam injection mold, and thereby form groove-like recesses in the foam body element which receive the upholstery cover material with the other corresponding adhesive fastener element. In this way geometric seam and shape patterns may be reproduced on a particular seat.
DE-A-199 56 011 discloses an adhesive fastener element for application for this purpose in the seating area, one having a support strip and interlocking elements mounted on the support strip. The support strip has at least one reinforcing element resistant to bending, one which extends preferably along the support strip in the form of a bending wire. Application of that solution results in better embedding properties in foam molds for adhesive fastener elements. Because of the flexural strength of the reinforcing element, once adhesive fastener elements have been introduced into the respective foam injection mold, they remain in their position. The cover strip is applied in one layer so as to be flush with the upper side of the foam injection mold. The possibility is then not to be excluded that, during the foam injection process itself preferably involving polyurethane foam, the foam may raise the cover strip above the side edges of the foam injection mold and so reach the interior of the channel-like injection mold in which the support strip with bending wire and the interlocking elements is seated. However, penetration of the intermediate areas of the interlocking elements by the foam weakens the fastening capability of these elements, so that they may not be effective when engaged with corresponding closing elements of the other component. This penetration on the whole reduces the adherence of the disclosed adhesive fastener elements.
To offset this disadvantage DE-A-100 39 940 discloses, for a generic adhesive fastener element, a cover strip which is wider than the support strip. The two free side edge areas of the cover strip are each folded back on themselves in the direction of the support strip along a fold line extending in the longitudinal direction. The end edges of the free side edge areas of the cover strip face the longitudinal edges of the support strip. As a result, the cover strip has on both sides a sealing lip which always extends along the area having the interlocking elements and which is adjacent to the wall elements of the foam injection mold enclosing the molding depression in which the interlocking elements are received during the foaming process. The foam material introduced into the foam injection mold causes this sealing lip to be pressed against the facing wall elements of the mold. As a result of the certain amount of flexibility in the area of the fold line, the sealing lip rests against the wall areas forming the sealing surface so that the improvement desired in the sealing action as foam barrier is achieved. In order then to impart a certain amount of flexural resistance to the adhesive fastener element, something which perceptibly improves handling during introduction into the foam injection mold, this disclosed solution also has a flexurally resistant element in the form of a bending wire.
Unintentional penetration of foam material in the direction of the interlocking elements may occur even with these disclosed solutions, despite this sealing lip configuration. It has been found in particular that the disclosed solution encounters its limits where the foam injection mold for design reasons has a configuration such that the disclosed solution with its side edge areas does not end flush and level with the upper side of a foam injection mold.